This invention is concerned with laryngoscopy, and particularly with improvements in laryngoscopes. In a more specific aspect the invention is directed to an improved laryngoscope blade.
Even though laryngoscopes were popularized by Magill over fifty years ago they are neverless in wide use today. Whereas the mouth, pharynx and larynx can be inspected by direct vision or by indirect mirror vision, it is only Possible to view the inner surfaces of the trachea and bronchi by peroral endoscopy. The most widely used instrument for peroral endoscopy is the laryngoscope.
In addition to endoscopy and inspection of the larynx, laryngoscopy is in frequent use in anesthesiology and in emergency medicine. Even though the introduction of anesthetics is most easily carried out by an intravenous administration, the use of endotracheal tubes is often necessary. Tracheal intubation requires the use of a laryngoscope. In addition the administration of anesthetics calls for reliable monitoring and control of ventilation. In emergency medicine laryngoscopy is not infrequently necessary for the diagnosis or removal of upper airway obstructions, and for tracheal intubation. Laryngeal tubes are also used, with simultaneou ventilation and anesthesia, if microsurgery in the region of the larynx is necessary. Laryngoscopy is thus quite common, even apart from emergency demands.
Through the years modifications have been made to improve Magill's straight blade laryngoscope. For example, by U.S. Pat. No. 2,433,705, (FIG. 1 herein) a light was added for better vision.
The laryngoscope light was improved by the invention of U.S. Pat. No. 4,592,343. A new light source was mounted so that it could be used with a conventional laryngoscope blade. The patent also shows a curved blade. Curved laryngeal blades are not as widely used as straight blades. Not only must they be inserted in the vallecula, but usually at some point during their introduction the curvature or hump obliterates the view.
In U.S. Pat. No. 4,360,008 a laryngoscope is provided having an adjustable distal end tip. The tip is selectively manually adjustable so that it can be disposed in any convenient angle relative to the main blade portion. With this pivotal tip soft tissue in the laryngeal area, such as the epiglottis, can be selectively displaced.
A different type of laryngoscope blade is shown in U.S. Pat. No. 4,573,451. This laryngoscope has a bendable or flexible tip. It is characterized as being easier to insert into a patients throat. It can be longitudinally pivoted with respect to the main body of the blade to move the epiglottis so as to expose the larynx.
It is to be emphasized that the use of a laryngoscope requires some surgical technique or experience. It is not easy to move the epiglottis forwardly while being careful not to injure the vocal cords. In U.S. Pat. No. 4,611,579 this problem is recognized. In order to make introduction easier, the laryngoscope blade of U.S. Pat. No. 4,611,579 is in the form of two components. They are joined at an angle of about 135 degrees to each other. The ratio of the length of one component to the length of the other is in the range of 4:5 to 4:3.
In considering laryngoscope improvements it should be understood that frequently this instrument is employed in emergency situations where the length of time one takes to insert the laryngeal blade is critical. Improvements which demand careful manipulation, and therefore result in loss of valuable seconds, are not the most desirable. Prolonged laryngoscope introduction which extends anoxia during the process is serious, and can be fatal. Laryngoscopes which do not function well under all conditions have not been widely accepted. By this invention a laryngoscope blade is provided which, like the prior art blades, is easier to use. It can also be more rapidly introduced. In addition it affords an advantage not considered by others, that of improving endotracheal intubation.